EP1146493B1 - Alarm device and method using power lines as communication means - Google Patents

Description

The invention relates to an alarm method and device comprising an alarm center provided with energy supply means autonomous electrics capable of ensuring its operation in mains power failure and at least one alarm detector connected to the alarm system by carrier current through the network supply of electrical energy to the home.

The present invention relates to the field of alarm systems for house with any means of detection, whether intrusion or other, such as smoke detectors, power supply cut off, etc.

Due to the evolution of home automation, more and more of homes are equipped with alarm systems whose connection of the different elements that compose them are linked together, not not by a dedicated network, but by carrier current, i.e. at across the electrical power supply network of this dwelling.

Such systems are described in US-A-4,603,318 and US-A-4,005,399.

Such a solution if, not only does it facilitate interconnection devices, also responds to the problem of their supply of electric energy. However, there is the problem of their operation in the event of a mains supply failure Housing.

The most suitable solution to date is to equip each detector, just like the power supply alarm center self-contained, usually in the form of rechargeable batteries. However, such batteries have a limited lifespan and it should be replaced periodically. AT less to take out a maintenance contract with a company able to manage such battery renewal times, their replacement rarely occurs in time. Either it is performed too early so that the corresponding expense is unnecessary, either it comes too late, which is more generally the case, and results from the finding of the alarm malfunction, for example, following an intrusion into the home by a burglar.

It seems obvious that for detectors, the management of such means autonomous power supply, in the form of batteries, is far from being simple and, as has just been demonstrated, these means are not able to respond effectively and in all cases to the problem, namely to insure, whatever happens in the event of a cut the mains supply of a home, the operation of intrusion detectors and, therefore, that of the alarm center. Of more, such batteries are relatively bulky for guarantee, as required, sufficient autonomy for these detectors and therefore pose the problem of miniaturization of these.

It should be noted that if there are other solutions than that batteries to guarantee an electrical energy supply autonomous electronic components, such as tank capacities, these are totally incapable of ensuring the operation of a carrier current transceiver during a sufficient time. It will be recalled on this subject that the microcontroller from the alarm center periodically checks the states logic of a detector, when it is powered by the sector, through the train of information transmitted at intervals regular time by this detector, by carrier current, audit microcontroller. Now this transmission of information by current carrier requires, over time, a greater amount of energy to that which such a tank capacity can deliver.

The object of the present invention is to provide the solution to the problem posed, making it possible for the alarm center to note the change of state of a detector, not supplied by the sector, while just monitoring the level of a signal in this last and, of course, without it being useful to equip this battery type autonomous power supply detector.

• en cas de coupure secteur, on émet, sur les fils du réseau et au travers de la centrale d'alarme, un signal, sensiblement sinusoïdal d'une fréquence déterminée F1 ;
• puis on surveille par l'intermédiaire de cette centrale d'alarme le niveau de la tension, sur ces mêmes fils du réseau, d'un signal dans une bande de fréquence étroite autour de la fréquence F1 et/ou d'un multiple entier de cette dernière, afin de détecter une perturbation de l'amplitude dudit signal résultant, selon le cas, d'une mise en court-circuit frauduleuse du réseau et/ou d'une modulation de l'impédance sur les fils de ce dernier à la fréquence F1 ou d'un multiple de cette fréquence provoquée par ledit détecteur en cas de detection d'alarme pendant ladite coupure secteur.

To this end, the invention relates first of all to a method for detecting an alarm in a home, comprising an alarm center provided with autonomous electrical power supply means provided capable of ensuring its operation in the event of a power outage and at least one alarm detector connected to the alarm center by carrier current through the electrical power supply network of the home, characterized in that:

• in the event of a power outage, a substantially sinusoidal signal of a determined frequency F1 is transmitted over the wires of the network and through the alarm center;
• then the voltage level, on these same network wires, of a signal in a narrow frequency band around the frequency F1 and / or an integer multiple of this is monitored by means of this alarm center the latter, in order to detect a disturbance in the amplitude of said signal resulting, as the case may be, from a fraudulent short-circuiting of the network and / or from a modulation of the impedance on the wires of the latter at the frequency F1 or a multiple of this frequency caused by said detector in the event of alarm detection during said power failure.

• la centrale d'alarme comporte d'une part, des moyens d'émission, en cas de coupure secteur; sur au moins deux fils dudit réseau, d'un signal sensiblement sinusoïdale, d'une fréquence F1 et, d'autre part, des moyens prévus aptes à surveiller le niveau de tension présent sur lesdits fils du réseau dans une bande de fréquence définie autour de la fréquence F1 et/ou d'un multiple entier de cette dernière afin de détecter une perturbation de l'amplitude dudit signal ;
• le ou les détecteurs d'alarme comportent des moyens qui, en cas de détection d'alarme lors d'une coupure secteur, sont conçus aptes à moduler l'impédance du réseau électrique sur les fils surveillés par la centrale d'alarme, à la fréquence F1 ou sensiblement autour de cette dernière et/ou de créer des harmoniques multiples de cette fréquence.

The invention also relates to an alarm device comprising an alarm center provided with autonomous electrical power supply means provided capable of ensuring its operation in the event of a power failure and at least one alarm detector, connected to the central alarm by carrier current through the electrical power supply network of the home, characterized in that:

• the alarm center comprises, on the one hand, transmission means, in the event of a power failure; on at least two wires of said network, of a substantially sinusoidal signal, of a frequency F1 and, on the other hand, means provided capable of monitoring the voltage level present on said wires of the network in a frequency band defined around frequency F1 and / or an integer multiple thereof to detect a disturbance in the amplitude of said signal;
• the alarm detector or detectors include means which, in the event of an alarm being detected during a power outage, are designed capable of modulating the impedance of the electrical network on the wires monitored by the alarm center, at the frequency F1 or substantially around it and / or create multiple harmonics of this frequency.

As for the means provided capable of ensuring this impedance modulation at the frequency F1 and / or a multiple thereof, they consist of the insertion on the wires of the network crossed by the signal from the alarm center, from a low LC circuit impedance in a defined band around the frequency F1 and at high impedance at other frequencies.

Insofar as a detector connected to an alarm center by carrier current is necessarily connected to the network by a pot home automation comprising a primary and a secondary, the modulation of the impedance advantageously results from the short-circuiting of the secondary of this home automation pot, taking into account that the frequency of signal emitted by the alarm center corresponds substantially to that on which is placed this home automation pot.

As will become apparent from the following detailed description, this secondary shorting of the home automation pot can intervene through means requiring only a small energy consumption, if any.

Therefore, other purposes and benefits arising from this invention will appear during this description below, whose understanding will be facilitated by referring to the attached drawing illustrating, in a single figure, a block diagram simplified device, object of the present invention.

Thus, the invention relates to a device 1 intended to be suitable, while specifically, to detect an alarm, such as an intrusion or an intrusion attempt, a device malfunction any or other, in a dwelling equipped with a central alarm 2.

This is connected by carrier current, therefore through network 3 supply of electrical energy to this home, to one or several 4,4A detectors, qualified in the following description of intrusion detectors taking into account that the present invention is in no way limited to detectors that exclusively fill this function.

In fact, the invention relates, first of all, to a process having for purpose of detecting an alarm in this home, even though there has been a cut in the electrical power supply at sector level 5 and therefore that the 4.4A detectors are no longer supplied by network 3. We also start from principle that these detectors do not include a power supply autonomous, battery type.

Thus, the method consists, in the event of a power outage, in transmitting, on wires 6,7 of network 3 and through the alarm center 2, a signal, substantially sinusoidal, pulsed or not, of a frequency determined F1, and then to monitor, through this alarm center 2 the voltage level, on these same wires 6.7 of network 3, of a signal in a narrow frequency band around the frequency F1 and / or an integer multiple thereof, in order to detect a disturbance in the amplitude of said signal resulting, as the case may be, from a fraudulent short-circuiting of the sector 4 and / or an impedance modulation on the wires 6,7 of the network 3 at frequency F1 or a multiple of this frequency caused by a 4.4A detector.

More particularly, the alarm center 2 of device 1 includes autonomous electrical energy supply means (not shown in the figure), such as a rechargeable battery, ensuring its operation during a power failure. She further comprises a carrier current transmitter-receiver assembly 8, whose transmission part 9 is provided capable of transmitting, through a current-carrying home automation pot 10, a bandpass filter 11 and a microcontroller 12, a sinusoidal signal of a frequency determined.

As for the reception part 13 of this transmitter-receiver assembly 8, it includes a first passive filter 14, then an active filter band pass 15, calibrated on the frequency of this sinusoidal signal, before to attack, through a rectifier without threshold 16, a analog-to-digital converter 17 of the microcontroller 12.

A 4.4A detector, when connected by carrier current to the alarm center 2, emits periodically, through the network 3 in the event of normal mains supply, a signal carrier current through which said power station 2 is informed of his state and, therefore, of any change of state following a detection. Also, it is connected by a 18,18A home automation pot to the wires 6.7 of the network to which the central is connected by its part transmission 9 and reception 13.

In this regard, it should be noted that he was not represented in the figure of the attached drawing the means, also known by a person skilled in the art, which ensures this emission of the states of a 4.4A detector, when this is normally supplied with electrical energy by network 3, therefore sector 5, only being illustrated the means allowing the implementation of the conforming process to the invention.

In particular, according to this invention, the alarm center 2 includes, in the event of a power outage, on the one hand, means transmission 9, on at least two wires 6,7 of said network 3, of a signal of a frequency F1 and, on the other hand, means 13 provided capable of monitor the voltage level present on said wires 6,7 of the network 3 in a frequency band defined around this frequency F1 and / or an integer multiple thereof.

The 4,4A detector (s) advantageously include means 19 which, in particular in the event of the detection of an intrusion or intrusion attempt during a sector 5 shutdown period, are designed to modulate the impedance of the electrical network 3, on the wires 6,7 monitored by alarm center 2, at frequency F1 or substantially around the latter and / or create multiple harmonics of this frequency.

Preferably, the frequency signal F1 is none other than that emitted in normal operation by alarm center 2, it is say in the presence of mains current, while the means for send it on the network go through the home automation pot of this alarm center 2. As for the means to monitor the level of voltage on wires 6,7 of network 3 in a frequency band defined, around this frequency F1, therefore of the current carrier carrier, they are, there again, constituted substantially by the current carrier reception part 13 of this alarm 2.

As for the means 19 allowing the impedance of the network 3 in case of alarm detection, they consist of means 21 to short-circuit the secondary 20.20A of the home automation pot 18.18A of the 4.4A detector which carried out the detection.

Thus, with regard to the detector identified 4 in the figure, these means 21 consist of a dry contact, of mechanical or ILS type 22, which, in the event of detection, is ordered to close without contribution of electrical energy. Note the presence of a relay 23 normally closed in the event of a mains 5 power failure and which therefore opens when the current is on again set this to disconnect the ILS from the circuit at that time.

As can be seen in the figure about the detector 4A, the means 21 to short-circuit the secondary 20A of the home automation pot 18A can also take the form of a transistor, of the MOS 24 type, the grid 25 is controlled either by a sensor without power supply, by example a piezoelectric or PVDF type shock sensor like visible in the figure, or any other sensor provided capable of operate for a certain duration, preferably several tens of hours, in ultra low energy consumption allowing its supply by a simple tank capacity. As example, we will mention passive infrared or infrasound sensors. Note that here, too, is visible in FIG. switch 26, normally open in the event of a power cut mains current, to connect the grid 25 of the MOS 24 to earth to make inactive these means for short-circuiting the pot home automation 18A, when on the contrary the mains current is established.

According to another embodiment, the means for short-circuiting the secondary of a home automation pot 18, 18A of a detector 4, 4a can take the form of a non-linear component, for example a schottky type detection diode, resulting in power failure in sector 5 and following a detection alarm, to create harmonics of frequency F1 on the network of the signal sent by the alarm center 2.

Ultimately, these means 19 for modulating the impedance of the network 3 can be defined, more generally, as means capable of insert on network 3 a serial LC circuit tuned to the frequency F1, of the signal emitted on this network by the alarm center.

According to an advantageous solution, the means 19 for modulating the impedance of the network 3 are defined, at the level of each detector, by a transponder using a frequency F2 different from the frequency F1 of the signal emitted by the alarm center 2, while being in the frequency band whose voltage level is monitored by said central.

Experiments were carried out with a signal sent to a frequency of the order of 132.5 kHz and a voltage, peak to peak, about 3 Volts. The secondary shorting of a pot home automation 18.18A, under these conditions and in the absence of current sector, causes a drop in this voltage to a level of the order a few millivolts.

The invention therefore proves to be particularly advantageous, insofar as the operation of an alarm installation carrier current no longer requires autonomous supply of detectors to enable them to perform their function by mains power failure, this over a period of time sufficient since it can reach several tens of hours with the contribution, for certain detectors, of a simple tank capacity.

Claims (9)

1. Process for detecting an alarm in a room including an alarm unit (2) provided with autonomous electric-current supply means designed capable of ensuring its operation in case of interruption of the supply network (5) and at least one sensor (4, 4A) connected to the alarm unit (2) by means of carrier current through the electric-current supply network (3) of the room, characterised in that:

   in the event of an interruption of the supply network (5), a substantially sine-wave signal at a determined frequency F1 is transmitted on the wires (6, 7) of the network (3) and through the alarm unit (2);

   then, through this alarm unit (2) is monitored the level of the voltage, on these same wires (6, 7) of the network, of a signal in a narrow frequency band around the frequency F1 and/or of an integer multiple of the latter, in order to detect a disturbance of the amplitude of said signal resulting, as the case may be, from a fraudulent short-circuiting of the network (3) and/or of a modulation of the impedance on the wires (6, 7) of the latter at the frequency F1 or a multiple of this frequency caused by said sensor (4, 4A) in the event of detection of an alarm during said interruption of the network (5).
2. Alarm device for implementing the process according to claim 1, including an alarm unit (2) provided with autonomous electric-current supply means designed capable of ensuring its operation in case of interruption of the supply network (5) and at least one sensor (4, 4A) connected to the alarm unit (2) by means of carrier current through the electric-current supply network (3) of the room, characterised in that:

   the alarm unit (2) includes, on the one hand, means (9) for transmitting, in the event of an interruption of the supply network, on at least two wires (6, 7) of said network (3), a substantially sine-wave signal at a frequency F1 and, on the other hand, means (13) designed capable of monitoring the level of the voltage present on said wires (6, 7) of the network in a narrow frequency band defined around the frequency F1 and/or of an integer multiple of the latter, in order to detect a disturbance of the amplitude of said signal;

   the sensor or sensors (4, 4A) including means (19) that, in the event of detection of an alarm during said interruption of the network (5), are designed capable of modulating the impedance of the network (3), on the wires (6, 7) monitored by the alarm unit (2), at the frequency F1 or substantially around the latter and/or of creating harmonics multiple of this frequency.
3. Device according to claim 2, characterised in that the means for transmitting the signal on the network (3) pass through the home repeater case (10) of this alarm unit (2) forming its carrier-current transmission portion (9).
4. Device according to claim 2 or 3, characterised in that the means for monitoring the level of the voltage on the wires (6, 7) of the network (3) in a defined frequency band around this frequency F1 and/or a multiple of the latter, are substantially formed by the carrier-current receiving portion (13) of this alarm (2).
5. Device according to any of claims 2 to 4, the sensor or sensors (4, 4A) of which are connected to the wires (6, 7) of the network (3) through a home repeater case (18, 18A), characterised in that the means (19) allowing modulating the impedance of the network (3) in case of detection of an alarm consist of means (21) for short-circuiting the secondary winding (20, 20A) of the home repeater case (18, 18A) of the sensor (4, 4A) having detected the intrusion.
6. Device according to claim 5, characterised in that the means (21) consist of a dry contact, of a mechanical type or ILS (22), connected to the secondary winding of the home repeater case (18, 18A).
7. Device according to claim 5, characterised in that the means (21) for short-circuiting the secondary winding (20A) of the home repeater case (18A) are formed by a MOS-type transistor (24) the grid (25) of which is controlled either by a sensor without current, for example a shock sensor of the piezoelectric or PVDF type or by any other sensor designed capable of operating for a determined period of time, preferably several dozens of hours, with an ultra-low energy consumption allowing its being supplied with electric current through a buffer capacity.
8. Device according to any of claims 2 to 7, characterised in that the means (19) for modulating the impedance of the network (3) are defined by means capable of inserting onto this network (3) a serial LC circuit tuned at the frequency F1, or preferably at the carrier-current frequency.
9. Device according to any of claims 2 to 7, characterised in that the means (19) for modulating the impedance of the network (3) are defined, at the level of each sensor (4, 4A), by a transponder using a frequency F2 different from the frequency F1 of the signal transmitted by the alarm unit (2), while remaining within the frequency band the level of the voltage of which is monitored by said unit (2).

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